Silk Cloth Farming in Razorfen Downs (Classic - WoTLK)
Razorfen Downs is a great place for you to farm both Silk Cloth and Mageweave Cloth. The mobs here will drop slightly more Silk than they will Mageweave, but this is one of the few instances where you'll get both at the same time. Assuming that you're only doing this instance to farm Silk Cloth you'll want to skip the escort quest and the gong boss. Basically, clear all the trash you can (and the final undead boss if you want) then zone out and reset the instance.
Those of you who have Herbalism will be able to make an extra profit from farming this zone. Throughout this instance you'll find Arthas' Tears, Goldthorn and Grave Moss, the latter two sell for a lot on the Auction House. Goldthorn is used in many different Agility potions (including the best ones) and Grave Moss, among other things, is used to make Shadow Oil which is then used for Greater Shadow Protection Potions. All of the green items that you find here I would recommend you vendor as they'll probably only disenchant into Vision Dust, which doesn't sell for too much.
If you have Enchanting, you will want to Disenchant the items that the bosses drop, most of the blues that you find here can be turned into Small Radiant Shards which are used in many commonly used Enchanting Recipes.
Last but not least, on the map above where you se "The Murder Pens" keep an eye out for any chests. In my personal experience it is not unusual to see a chest spawn in this location which will net you some extra silver and goodies you can sell on the AH.
Items of Interest
Silk Cloth
Mageweave Cloth
Arthas' Tears
Goldthorn
Grave Moss